Numerous methods have been proposed for the oxidation removal of contaminating materials from aqueous liquids.
Furthermore, a large number of adsorption methods have been proposed, for this purpose which however give rise to difficulties in their application since their degree of efficacy is dependent on knowledge of the polluting materials to be adsorbed.
Generally materials can only be adsorbed when the adsorbing material has an opposite charge.
Therefore, known adsorption methods are applicable if it is only a question of a few known contaminating materials in the liquids, which are to be removed. If the materials in the liquid are neutral, the adsorbing means then remain without effect.
In many cases these polluted liquids comprise conglomerates of contaminating materials which make it necessary to use a large number of adsorbing materials arranged one after the other. Such adsorption stages, arranged sequentially, give rise to disadvantages when they are regenerated. In the case of chemical regeneration many different types of eluates are produced which are difficult to handle; thermal regeneration is to be objected to on the grounds of its costs and complexity. Neutral liquid contaminants cannot be adsorbed at all unless they are previously transformed.